1. Field of the Invention
One aspect of the present invention relates generally to brush chippers which have a manually controlled upper feed stop member with four positions, which sequentially from forward to rear of the upper feed stop member are stop, forward, neutral and reverse, and a lower feed stop member which serves to shut off the feed mechanism of the brush chipper when it is moved forwardly by a predetermined distance or angle. This aspect of the present invention relates more particularly to such a brush chipper wherein the lower feed stop member has more than one stop position and specifically wherein the operator can adjust the stop position between one or more positions to make it more sensitive or less sensitive, depending upon the working conditions. The present invention also relates to such a lower feed stop member having a feature to re-set it to a predetermined setting after each use of the brush chipper. Other aspects of the invention relate to predictability, feed roller stop and reverse, overcoming jamming, program selection and idle down.
2. Description of the Related Art
Upper and Lower Feed Stop
Some prior art brush chippers have only a manually controlled upper feed stop member with three positions, forward, neutral and reverse. Other prior art brush chippers, particularly those used in Europe, also have a lower feed stop member, having one shut-off position. This lower feed stop member is disposed just below the feed table and typically is pivotally attached to the frame and has a forward position and a rearward position, forward being the front when considering the direction of flow of the brush through the machine and rearward being the place where the brush enters the feed table. A problem with prior art devices is that when larger branches are inserted onto the feed table that means that larger sub-branches will also emanate from such branch. These larger downwardly extending branches often hit the lower feed stop member and shut off the feed mechanism of the brush chipper at times when the operator actually wants the feed mechanism to continue to operate. In addition to size, the shape or stiffness of the downwardly extending branches also affect whether the lower control bar is activated. While these prior art brush chippers operate just fine when smaller branches are fed into the brush chipper, the problem primarily exists during the time that larger or stiffer sub-branches are being fed into the brush chipper. It is perceived that if the machine is constantly being shut off by the lower feed stop bar when larger branches are being fed into the machine, there is a danger that an operator might attempt to disable the shut off mechanism so that he can continue to finish the job of chipping larger branches without the inconvenience of having the brush chipper shut itself off frequently, i.e. nuisance stops.
Consequently, there is a need for a brush chipper having a lower feed stop member which will overcome the aforementioned disadvantages. Also, upper feed stop control members usually have only three positions, forward, neutral and reverse. This limits their usefulness, especially in combination with other aspects of the present invention.
Predictability
If a larger log is being chipped, the engine decelerates quickly and this will stop the feed rollers more quickly than if a smaller log or branches are being chipped. Prior art devices do not distinguish between the two. There is an advantage in using this information in the control of a brush chipper which advantage is not currently being used by the prior art.
Feed Roller Reversing
The engine needs to re-accelerate in order to work in an optimum manner. Even when the feed rollers are stopped from feeding material into the cutter mechanism, the engine rpm may not accelerate. This can be due to drag caused by a log or the like rubbing against the cutter mechanism. So merely stopping the feed rollers may not be sufficient to solve the problem. The present invention presents a solution to this problem
Overcoming Jamming
In the prior art, occasionally, the material being fed into the chipper will become oriented so it catches on the feed table, the infeed opening, or elsewhere. The hydraulically powered feed rollers will then stall and the hydraulic oil will be redirected through the relief valve. Often the operator need only manually operate the upper feed control bar to momentarily reverse the feed rollers and return to the forward feed position to reorient the material so that it will continue feeding. The present invention provides an automatic solution to this problem.
Program Selection
Controllers for brush chippers can have more than one program for use depending upon certain parameters, such as the size of the engine, etc. The present invention provides an automatic solution to program selection which is not available in the prior art.
Idle Down
During the chipping process, there are times when the chipper is running at a high rpm but is not being used for chipping. This could be due to an operator hauling branches to the chipper, moving the chipper to another location, or the operator being distracted for some reason and not using the chipper. This causes fuel to be used unnecessarily and causes unnecessary wear and tear on the brush chipper. The present invention provides an automatic solution to this problem.